AB0494 COMPARISON OF CUTANEOUS SILENT PERIOD PARAMETERS IN PATIENTS WITH PRIMARY SJÖGREN’S SYNDROME WITH THE HEALTHY POPULATION
Authors: G. Yolcu, K. Abacar, O. Kenis-Coskun, N. Inanc, E. Karadag-Saygi, O. H. Gunduz
Journal: Annals of the Rheumatic Diseases (2022)

Background Neurological involvement has a great importance in the clinical spectrum of primary Sjögren’s syndrome (pSS) (1). The presence of small fiber neuropathy (SFN), which cannot be detected in routine electrophysiological examinations, causes the peripheral nervous system involvement to be underestimated in the course of the disease and causes pain-related symptoms in patients that cannot be explained by routine examinations (2). Various methods can be used in the detection of SFN, and cutaneous silent period (CSP) measurement is gaining popularity recently due to its non-invasiveness and practical application (3). Objectives Evaluating SFN involvement in patients with pSS using CSP and evaluating its relationship with clinical parameters. Methods Patients with a diagnosis of pSS followed in the rheumatology outpatient clinic and healthy volunteers demographically homogeneous with the patient group were included in the study. The CSP responses were recorded over the abductor pollicis brevis muscle in the upper extremity of all participants. The latency and duration values of the responses were obtained. In patient group, EULAR Sjögren’s Syndrome Patient Reported Index (ESSPRI), Hospital Anxiety and Depression Scale (HADS), Short Form-36 (SF-36) questionnaire, Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and Central Sensitization Inventory (CSI) were applied for the evaluation of symptom severity, mood, quality of life, presence of neuropathic pain and central sensitization, respectively. Comparison of CSP parameters between patients with pSS and healthy volunteers was determined as the primary outcome measure. The secondary outcome measure was the relationship between CSP parameters and ESSPRI, HADS, SF-36, LANSS and CSI scores. Results A total of 36 patients and 36 healthy controls were included in the final analyses. There was no significant difference between the two groups in terms of demographic data. The mean CSP latency was significantly longer in patients with a mean of 78.18 (±7.51) when compared to controls with a mean of 67.91 (±6.41) (95% CI: 6.98- 13.55, p&lt;0.001). Mean CSP duration was also significantly shorter in patients with a mean of 33.40 (±6.93) (95% CI: 9.57 -15.31, p&lt;0.001). There were no significant differences in CSP parameters (latency and duration, respectively) according to patients’ neuropathic pain or central sensitization profile (p&gt;0.05 for all analyses). There were significant correlations of CSP parameters with ESSPRI dryness (r=0.469, p=0.004; r=-0.553, p&lt;0.001), fatigue (r=0.42, p=0.011; r=-0.505, p=0.002), pain (r=0.428, p=0.009; r=-0.57, p&lt;0.001) subscores and mean ESSPRI score (r=0.631, p&lt;0.001; r=-0.749, p&lt;0.001). Significant correlations were not found between CSP parameters and SF-36 scores, other than CSP duration and “pain” subscore (r=-0.395, p=0.017). When the other correlations were investigated there were no significant correlations other than CSP duration and the HADS anxiety score (r=-0.201, p=0.02). Conclusion As an indicator of CSP measurement, SFN is more common in patients with pSS than in the healthy population. The association with important clinical symptoms of the disease course such as dryness, fatigue, pain and anxiety highlights the importance of detecting small fiber neuropathy. References [1]Margaretten M. Neurologic manifestations of primary Sjögren syndrome. Rheumatic Disease Clinics. 2017;43(4):519-29. [2]Birnbaum J, Lalji A, Saed A, Baer AN. Biopsy-Proven Small-Fiber Neuropathy in Primary Sjögren’s Syndrome: Neuropathic Pain Characteristics, Autoantibody Findings, and Histopathologic Features. Arthritis Care Res (Hoboken). 2019 Jul;71(7):936-948. [3]Tekatas A, Tekatas DD, Solmaz V, Karaca T, Pamuk ON. Small fiber neuropathy and related factors in patients with systemic lupus erythematosus; the results of cutaneous silent period and skin biopsy. Advances in Rheumatology. 2020 Jun 15;60. Disclosure of Interests None declared